Image delivery management server and image delivery management system

ABSTRACT

An image delivery management server of present invention includes a delivery load amount acquiring portion that acquires a delivery load amount of an image that is delivered to a viewer&#39;s terminal connected via a network, and a delivery device determining portion that determines, based on the delivery load amount, a type or a quantity of a delivery device that performs image delivery to the viewer&#39;s terminal.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent ApplicationNo. JP 2010-082338 filed in the Japanese Patent Office on Mar. 31, 2010,the entire content of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image delivery management server andan image delivery management system.

2. Description of the Related Art

In known art, for example, Japanese Patent Application Publication No.JP-A-2009-118319 describes a method to determine whether content shouldbe delivered or not based on information relating to a network surplusvalue and network utilization bandwidth. Further, Japanese PatentPublication No. 4083169 describes a method to determine whether contentshould be delivered or not using a load factor table, hourly historicaldata etc. when lines are switched between a spare line and an operationline depending on a load factor.

SUMMARY OF THE INVENTION

However, with the technology described in Japanese Patent ApplicationPublication No. JP-A-2009-118319, since the technology only performsdelivery from a delivery server, it is assumed that it becomes difficultto perform the delivery when a load on the delivery server becomes high.Further, with the technology described in Japanese Patent PublicationNo. 4083169, since a number of server lines is increased in accordancewith an increase of a delivery load, problems arise in which a structurethat includes the server becomes complex and a cost increase isincurred.

Therefore, in light of the foregoing, the present invention provides anovel and improved image delivery management server and image deliverymanagement system that are capable, with a simple structure, ofdetermining a delivery device in accordance with an image delivery load.

According to an embodiment of the present invention, there is providedan image delivery management server includes a delivery load amountacquiring portion that acquires a delivery load amount of an image thatis delivered to a viewer's terminal connected via a network, and adelivery device determining portion that determines, based on thedelivery load amount, a type or a quantity of a delivery device thatperforms image delivery to the viewer's terminal.

In this configuration, the delivery load amount acquiring portionincludes a viewer's terminal information acquiring portion that acquiresinformation relating to the viewer's terminal to which the image isdelivered, and the delivery device determining portion determines thetype or the quantity of the delivery device in accordance with theinformation relating to the viewer's terminal.

In this configuration, the information relating to the viewer's terminalincludes at least a current or past number of viewers to which the imageis delivered or a number of viewers who have reserved the image that isto be delivered.

In this configuration, the delivery load amount acquiring portionfurther includes a utilization bandwidth acquiring portion that acquiresa utilization bandwidth of the network that is used by the imagedelivery, and the delivery device determining portion determines thetype or the quantity of the delivery device based on a number of viewersand the utilization bandwidth.

In this configuration, the delivery device includes at least one of atleast one delivery terminal that directly delivers the image to theviewer's terminal and a delivery server that delivers an image uploadedfrom the delivery terminal to the viewer's terminal.

In this configuration, the delivery device determining portiondetermines the quantity of the delivery terminal that delivers the imageto the viewer's terminal based on a predetermined threshold valuerelating to one of the number of viewers and the utilization bandwidth,and also determines whether only the delivery server delivers the imageto the viewer's terminal.

In this configuration, the delivery device determining portion increasesthe quantity of the delivery terminal that delivers the image inaccordance with an increase of one of the number of viewers and theutilization bandwidth, and determines that only the delivery serverdelivers the image to the viewer's terminal, when one of the number ofviewers and the utilization bandwidth exceeds the predeterminedthreshold value.

In this configuration, the delivery device determining portion makes aswitch from delivery using only the delivery server to delivery using aplurality of the delivery terminals, when one of the number of viewersand the utilization bandwidth becomes less than or equal to thepredetermined threshold value, and also decreases the quantity of thedelivery terminals by which the image is delivered in accordance with afurther decrease of one of the number of viewers and the utilizationbandwidth.

In this configuration, the delivery device determining portion causesboth a device that is made to stop delivering and a device that is madeto continue delivering to temporarily deliver an image stream, when thedelivery using only the delivery server is switched to the deliveryusing the plurality of the delivery terminals or when the quantity ofthe delivery terminals is decreased.

In this configuration, the delivery device determining portion causesboth the device that is made to stop delivering and the device that ismade to continue delivering to temporarily deliver the image stream andalso makes the bandwidth of each of the image stream narrower thanusual, when the delivery using only the delivery server is switched tothe delivery using the plurality of the delivery terminals or when thequantity of the delivery terminals is decreased.

According to another embodiment of the present invention, there isprovided an image delivery system includes an image delivery managementserver, a delivery device and a viewer's terminal. The image deliverymanagement server includes a delivery load amount acquiring portion thatacquires a delivery load amount of an image that is delivered to aviewer's terminal connected via a network, and a delivery devicedetermining portion that determines, based on the delivery load amount,a type or a quantity of a delivery device that performs an imagedelivery to the viewer's terminal. The delivery device is connected tothe image delivery management server and the viewer's terminal via thenetwork. The viewer's terminal is connected to the image deliverymanagement server and the delivery device via the network.

According to the present invention, it is possible to provide a noveland improved image delivery management server and image deliverymanagement system that are capable, with a simple structure, ofdetermining a delivery device in accordance with an image delivery load.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A and FIG. 1B are schematic diagrams respectively showing anoverview of a method to deliver live video images;

FIG. 2 is a schematic diagram showing a structure of a general livevideo image delivery network corresponding to FIG. 1A;

FIG. 3 is a schematic diagram showing a structure of a network thatdirectly delivers the live video images, as illustrated in FIG. 1B;

FIG. 4 is a diagram showing a video image delivery input/output using adelivery terminal in the structure shown in FIG. 3;

FIG. 5 is a schematic diagram showing a network structure of livedelivery using an available delivery terminal;

FIG. 6 is a schematic diagram showing a viewing start sequence of aviewing user;

FIG. 7 is a sequence diagram showing delivery start processing by adelivery provider of the live video images;

FIG. 8 is a schematic diagram showing information that is managed on adatabase within a delivery management server;

FIG. 9 is a flow chart showing processing by the delivery managementserver to select an optimum delivery method before starting the videoimage delivery;

FIG. 10 shows a method to determine the optimum delivery method whilethe live video images are being delivered;

FIG. 11 shows the method to determine the optimum delivery method whilethe live video images are being delivered;

FIG. 12 is a schematic diagram showing a functional block structure ofthe delivery management server;

FIG. 13 is a sequence diagram of a case in which use of the availabledelivery terminal or a delivery server newly starts after a predictednumber of viewers or a predicted utilization bandwidth increases;

FIG. 14 is a sequence diagram of a case in which use of the currentlyused available delivery terminal or delivery server is ended after thepredicted number of viewers or the predicted utilization bandwidthdecreases;

FIG. 15 is a schematic diagram showing a method to temporarily establisha connection to the video image delivery of a narrow bandwidth whenterminals are switched;

FIG. 16 is a sequence diagram showing the method illustrated in FIG. 15in detail.

DETAILED DESCRIPTION OF THE EMBODIMENT(S)

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the appended drawings. Note that,in this specification and the appended drawings, structural elementsthat have substantially the same function and structure are denoted withthe same reference numerals, and repeated explanation of thesestructural elements is omitted.

Note that an explanation will be given below in the following order.

Overview of system of present embodiment

Specific structural example of system according to present embodiment

Processing sequence of system according to present embodiment

1. Overview of System of Present Embodiment

FIG. 1A and FIG. 1B are a schematic diagrams respectively showing anoverview of a method to deliver live video images. FIG. 1A shows astructure in which live video images taken at a sports event, a concertetc. are collected into a moving image delivery server 100 and the livevideo images are transmitted from the moving image delivery server 100to a viewing terminal 200 of each user. The transmission by the movingimage delivery server 100 makes it possible to deliver the live videoimages to many of the viewing terminals 200, but it has a disadvantagein that a delivery cost becomes high. On the other hand, FIG. 1B shows astructure in which live video images are directly transmitted from adelivery terminal 300 to the viewing terminal 200, the delivery terminal300 having captured the live video images. In this case, a heavy load isnot put on the moving image delivery server 100, but there is adisadvantage in that the number of live video images that can bedelivered becomes smaller.

2. Concrete Structural Example of System According to Present Embodiment

A detailed explanation will be made below with reference to FIG. 2. FIG.2 is a schematic diagram showing a structure of a general live videoimage delivery network corresponding to FIG. 1A. A delivery provider whoperforms a delivery uploads the live video images from the deliveryterminal 300 to the moving image delivery server 100 and the movingimage delivery server 100 delivers the live video images to the viewingterminal 200. A high performance device that has high moving imagedelivery performance etc. is used as the moving image delivery server100. Further, by using a network having a large bandwidth as a network1000 to which the moving image delivery server 100 is connected and byusing a technology such as multi-cast technology, it becomes possible toperform delivery of the moving images to more than or equal to severalthousands of the viewing terminals 200. On the other hand, since thedevice such as the high performance moving image delivery server 100 andthe network 1000 that has the large bandwidth are used in the structureshown in FIG. 2, when the moving images are delivered to a small numberof the viewing terminals 200, the method shown in FIG. 2 becomesrelatively expensive compared with a method shown in FIG. 3 that will beexplained below.

FIG. 3 is a schematic diagram showing a structure of a network thatdirectly delivers the live video images, as illustrated in FIG. 1B. Inthe structure shown in FIG. 3, the live video images are directlydelivered from the delivery terminal 300 to the viewing terminal 200 viaa network 1200 without going through the moving image delivery server100. Due to an increased network bandwidth of a household-use networkand an improved capability of a personal computer (PC) in recent years,even with respect to high definition (HD) live video images, it ispossible to deliver the live video images to tens of the viewingterminals 200 by using the structure shown in FIG. 3. With the structureshown in FIG. 3, compared with the delivery method shown in FIG. 2,since it is not necessary to prepare the high performance device nor adedicated network with a large bandwidth, it is possible to performdelivery at a relatively low cost. On the other hand, with the structureshown in FIG. 3, since a capability of the delivery terminal 300 islower than the moving image delivery server 100 and a bandwidth of thenetwork 1200 is smaller than that of the network 1000 shown in FIG. 2,some difficulties are incurred when delivering the live video images toa large number of the viewing terminals 200.

FIG. 4 is a diagram showing a video image delivery input/output usingthe delivery terminal 300 in the structure shown in FIG. 3. A videoimage is input into the delivery terminal 300 from a camera (an imagingdevice) 500 or another of the delivery terminals 300. The video imagemay be input either via a wire (a cable) or via a network. The deliveryterminal 300 can deliver the video image that is input to a plurality ofthe viewing terminals 200.

FIG. 5 is a schematic diagram showing a network structure for livedelivery using an available delivery terminal 302 (a delivery terminalthat is not being used). Since the delivery terminal 300 can alsodeliver the video image that is input via the network, the deliveryterminal 300 utilizes the available delivery terminal 302, which is notcurrently being used, as a booster for delivering the live video imageswhile using this function. When it is assumed that a total number of theviewing terminals 200 to which each of the delivery terminals 300 andeach of the available delivery terminals 302 can deliver the live videoimages is N, it becomes possible to deliver the live video images to atotal number N of the viewing terminals 200 by using the availabledelivery terminal 302. With this delivery method, it is possible toperform the live delivery to a larger number of the viewing terminals200 than a number of the viewing terminals 200 to which the live videoimages can be directly delivered using only the delivery terminal 300illustrated in FIG. 3. On the other hand, when the number of the viewingterminals 200 becomes large, the delivery using the moving imagedelivery server 100 shown in FIG. 2 becomes advantageous in terms ofcost. Therefore, a delivery method shown in FIG. 5 is suitable fordelivery when the number of the viewing terminals 200 is less than thenumber of the viewers for which the moving image delivery server 100shown in FIG. 2 is considered appropriate in terms of delivery cost.

As described above, it is possible to select the delivery method forperforming efficient live delivery in an optimum manner by using thedelivery terminal 300 and the moving image delivery server 100appropriately depending on the number of the viewing terminals 200.

FIG. 6 is a schematic diagram showing a viewing start sequence of aviewing user. First, the viewing terminal 200 is connected to a deliverymanagement server 400 (step S10) and obtains a program guide. When theuser selects a program that he/she wants to view from the program guide,the fact that the program has been selected by the user is notified tothe delivery management server 400 (step S12). If the program selectedby the viewing terminal 200 is currently being broadcast, the deliverymanagement server 400 notifies the viewing terminal 200 of informationregarding the delivery terminal 300 (or the available delivery terminal302) or the moving image delivery server 100 (step S14), namelyinformation regarding whichever is currently delivering the live videoimages. On the basis of the notified information, the viewing terminal200 is connected to the delivery terminal 300, to the available deliveryterminal 302 or to the moving image delivery server 100, whichever isdelivering the live video images (step S16), and reception of the livevideo images is started (step S18).

Further, if the program selected by the viewing terminal 200 is not yetbeing broadcast, when the program is selected, it is stored in thedelivery management server 400 that the program is reserved. Then, whenthe program starts being delivered, the viewing terminal 200 is notifiedof information regarding the delivery terminal 300, the availabledelivery terminal 302 or the moving image delivery server 100 (whicheveris delivering the live video images that have been reserved), and itbecomes possible to receive the live video images. In the deliverymanagement server 400, information noting that the program has beenreserved is used for making a delivery determination to performefficient live delivery.

By using the sequence shown in FIG. 6, it is possible for the user toreceive the live video images using a substantially similar mechanismwithout being influenced by different types of device on a delivery side(the moving image delivery server 100, the delivery terminal 300 and theavailable delivery terminal 302).

FIG. 7 is a sequence diagram showing delivery start processing by adelivery provider of the live video images. The delivery terminal 300registers program information to the delivery management server 400 inadvance (step S12). The delivery management server 400 adds theregistered program information to the program guide, determines anoptimum delivery method at a certain timing before starting delivery(step S21) and notifies the delivery terminal 300 (step S22). When thedelivery terminal 300 is instructed by the delivery management server400 to use the available delivery terminal 302 or the moving imagedelivery server 100, the delivery terminal 300 is connected to thespecified terminal (the available delivery terminal 302 or the movingimage delivery server 100) (step S24) and moving image delivery isperformed (step S26). In this case, the live video images aretransmitted from the delivery terminal 300 to the available deliveryterminal 302 and then from the available delivery terminal 302 to theviewing terminal 200. Alternatively, the live video images are uploadedfrom the delivery terminal 300 to the moving image delivery server 100and then transmitted from the moving image delivery server 100 to theviewing terminal 200. Further, when the delivery terminal 300 isinstructed by the delivery management server 400 to directly deliver thelive video images, after being connected by the viewing terminal 200(step S28), the delivery terminal 300 performs delivery of the videoimages (step S29).

Next, a method for the delivery management server 400 to select theoptimum delivery method at step S21 in FIG. 7 will be explained. FIG. 8is a schematic diagram showing information that is managed on a databasewithin the delivery management server 400. As shown in FIG. 8, a programguide database and a delivery terminal management database are managedon the database within the delivery management server 400. The programguide database manages such information as a program name, a deliveryprovider, a delivery time, a number of viewers who have reserved aprogram (a number of viewer reservations) and a number of currentviewers (a number of viewers). The delivery terminal management databasemanages such information as a delivery terminal name, a deliveryterminal IP address, a maximum potential number of deliveries, a currentstatus of the delivery server and a current number of deliveries.

FIG. 9 is a flow chart showing processing by the delivery managementserver 400 to select the optimum delivery method before starting thevideo image delivery. In the processing shown in FIG. 9 a determinationis made at the certain timing before delivering the video image. Basedon the processing shown in FIG. 9, the delivery management server 400predicts that the number of viewers for a chosen program will be largewhen a number of viewer reservations, an average number of viewers thathave viewed the program delivered by the delivery provider in the past,or a predicted number of viewers of the moving images exceed a certainnumber. In such a case, the delivery management server 400 determinesthat it is optimum to use the moving image delivery server 100 for thedelivery. In specific terms, at step S30, step S32 and step S34 shown inFIG. 9, when one of the following conditions is satisfied, namely whenthe number of viewer reservations for the program is larger than A(number of people), when the average number of viewers who have viewedthe program in the past is larger than B (number of people) or when thepredicted number of moving image viewers is larger than C (number ofpeople), the processing proceeds to step S36. At step S36, delivery isperformed using the moving image delivery server 100. Further,parameters that can predict the number of viewers may be added as otherconditions, the parameters including a number of people who participatein a community created by the delivery provider, or a number of userswho register the delivery provider as their “favorite” etc.

On the other hand, when it is predicted that the number of viewers willbe small, the moving image delivery server 100 is not used. In specificterms, when none of the conditions at step S30, step S32 and step S34shown in FIG. 9 is satisfied, the processing proceeds to step S38. Then,at step S38 and at step S40, when one of the following conditions issatisfied, namely when the number of viewer reservations for the programis less than the maximum potential number of deliveries by the deliveryterminal 300 or when a total bandwidth required for the video imagedelivery is smaller than the network bandwidth of the delivery terminal300, the processing proceeds to step S44, since it can be determinedthat a capability of the delivery terminal 300 on its own is notsufficient to perform the delivery, and the delivery that also uses theavailable delivery terminal 302 is performed.

Further, at step S38 and at step S40, when the maximum potential numberof deliveries is larger than or equal to the number of viewerreservations for the program and when the total bandwidth required forthe video image delivery is larger than or equal to the networkbandwidth of the delivery terminal 300, the processing proceeds to stepS42. In this case, since it is possible to perform a direct deliveryfrom the delivery terminal 300, the direct delivery is performed fromthe delivery terminal 300 at step S42.

Selection of the available delivery terminal 302 is performed from thedelivery terminal management database shown in FIG. 8. At this time, inorder to make it possible to perform efficient delivery, a similarprovider to a provider that is used by the delivery terminal 300 may beselected, or the available delivery terminal 302 that is reliablyavailable until the program finishes may be deliberately selected.

Although the optimum delivery method is selected before a start ofbroadcast by using the above-described method, the optimum deliverymethod may change during the broadcast due to a change in the number ofviewers. For example, when the number of viewers increases during thebroadcast (when the video images are being delivered), due to aninsufficient capability of the delivery terminal 300 or an insufficientbandwidth of the network 1000 to which the delivery terminal 300 isconnected, it is possible that it becomes unable to deliver the videoimages to new viewers. Further, when the number of viewers decreasesduring the broadcast, it is possible that the delivery terminal 300 orthe moving image delivery server 100, which has an excessive capabilitywith respect to the current number of viewers, may continue to be used.

FIG. 10 and FIG. 11 show a method to determine the optimum deliverymethod while the live video images are being delivered. Processing shownin FIG. 10 and FIG. 11 is performed at certain intervals while the livevideo images are being delivered. First, as shown in FIG. 10, apredicted value of the number of viewers is calculated. As shown in FIG.10, the predicted value of the number of viewers (a predicted number ofviewers) is a value that is obtained by multiplying a number of viewersCi and a coefficient αi and summing all the multiplied results, thenumber of viewers Ci being sampled at certain intervals between a time xin the past and a present time y. A sum of the coefficient αi is 1, andthe closer αi values are to the present time the values become larger sothat a trend closer to the present time has a greater impact on thepredicted value. Next, a predicted value of a utilization bandwidth iscalculated. As shown in FIG. 10, the predicted value of the utilizationbandwidth (a predicted utilization bandwidth) is a value obtained bymultiplying a number of viewers Bi and a coefficient βi and summing allthe multiplied results, the number of viewers Bi being sampled atcertain intervals between the time x in the past and the present time y.

Next, as shown in FIG. 11, threshold values CTH low_(—)1, BTH low_(—)1,CTH high_(—)1 and BTH high_(—)1 are calculated in advance, and based onthe threshold values, it is determined whether the delivery is performedusing the delivery server or the delivery is performed using an n numberof the available delivery terminals. Here, the threshold value CTHlow_(—)1 is a threshold value for the predicted number of viewers, andwhen the predicted number of viewers is greater than or equal to thethreshold value, it can be determined that the “delivery using the nnumber of the available delivery terminals” is cheaper than the“delivery using the delivery server” in terms of cost, and that thedelivery can be performed in terms of capability. Further, the thresholdvalue BTH low_(—)1 is a threshold value for the predicted utilizationbandwidth, and when the predicted utilization bandwidth is greater thanor equal to the threshold value, it can be determined that the “deliveryusing the n number of the available delivery terminals” is moreappropriate than the “delivery using the delivery server” in terms ofthe utilization bandwidth.

As shown in FIG. 11, when the delivery using the moving image deliveryserver 100 is performed at step S40, if both conditions at step S42 andat step S44 are satisfied, the processing proceeds to step S46, and thedelivery using the n number of the available delivery terminals 302 isperformed. In other words, when the predicted number of viewers≦CTHlow_(—)1 is satisfied at step S42 and the predicted utilizationbandwidth≦BTH low_(—)1 is satisfied at step S44, the processing proceedsto step S46, and the delivery using the n number of the availabledelivery terminals 302 is performed. In this way, when the “deliveryusing the delivery server” is currently being performed, if thepredicted number of viewers is less than or equal to CTH low_(—)1 andthe predicted utilization bandwidth is less than or equal to BTHlow_(—)1, it is determined that the “delivery using the n number of theavailable delivery terminals” is optimum.

Further, when the delivery using the n number of the available deliveryterminals 302 is being performed at step S46, if both conditions at stepS48 and at step S49 are satisfied, the processing proceeds to step S40,and the delivery using the moving image delivery server 100 isperformed. In other words, when the predicted utilization bandwidth≧BTHhigh_(—)1 is satisfied at step S48 and the predicted number ofviewers≧CTH high_(—)1 is satisfied at step S49, the processing proceedsto step S40, and the delivery using the moving image delivery server 100is performed. In this way, when the delivery using the n number of theavailable delivery terminals is currently being performed, if thepredicted utilization bandwidth exceeds BTH high_(—)1 or the predictednumber of viewers exceeds CTH high_(—)1, it is determined that the“delivery using the delivery server” is optimum.

In a similar manner, threshold values CTH low_k, BTH low_k, CTH high_kand BTH high_k are threshold values by which it is determined whetherdelivery is performed using a single one of the available deliveryterminals 302 or by direct delivery from the delivery terminal 300. Asshown in FIG. 11, the threshold values CTH low_k, BTH low_k, CTH high_kand BTH high_k are calculated in advance, and based on the thresholdvalues, it is determined whether the delivery using the n number of theavailable delivery terminals 302 or the direct delivery from thedelivery terminal 300 is performed. Note that although part of anillustration is omitted in FIG. 11, when it is determined whether thedelivery using the n number of the available delivery terminals 302 isperformed or not, the threshold values CTH low_k, BTH low_k, CTH high_kand BTH high_k are different with respect to each different n value.Then, with respect to each different n value, the threshold values CTHlow_k, BTH low_k, CTH high_k and BTH high_k are set individually.Therefore, as a result of comparison with the respective thresholdvalues, it can be determined how many of the available deliveryterminals 302 are to be used to perform the delivery.

As shown in FIG. 11, when the delivery using one of the availabledelivery terminals 302 is performed at step S50, if both conditions atstep S52 and at step S54 are satisfied, the processing proceeds to stepS56, and the direct delivery from the delivery terminal 300 isperformed. In other words, when the predicted number of viewers≦CTHlow_k is satisfied at step S52 and the predicted utilization bandwidthBTH low_k is satisfied at step S54, the processing proceeds to step S56,and the direct delivery from the delivery terminal 300 is performed.

Further, when the direct delivery from the delivery terminal 300 isbeing performed at step S56, if both conditions at step S58 and at stepS59 are satisfied, the processing proceeds to step S50, and the deliveryusing one of the available delivery terminals 302 is performed. In otherwords, when the predicted utilization bandwidth≧BTH high_k is satisfiedat step S58 and the predicted number of viewers≧CTH high_k is satisfiedat step S59, the processing proceeds to step S50, and the delivery usingone of the available delivery terminals 302 is performed.

As described above, the delivery management server 400 selects theoptimum delivery method from methods including the “delivery using thedelivery server”, the “delivery using one of the available deliveryterminals”, the “delivery using the n number of the available deliveryterminals” and the “direct delivery from the delivery terminal”. FIG. 12is a schematic diagram showing a functional block structure of thedelivery management server 400. As shown in FIG. 12, the deliverymanagement server 400 includes a delivery load amount acquiring portion410, a delivery device determining portion 420, a program guide database430 and a delivery terminal management database 440. The delivery loadamount acquiring portion 410 includes a number of viewers acquiringportion 412 and a utilization bandwidth acquiring portion 414. Thenumber of viewers acquiring portion 412 acquires the number of viewersusing the above-described method, and the utilization bandwidthacquiring portion 414 acquires the utilization bandwidth using theabove-described method. Based on a delivery load (the number of theviewers, the utilization bandwidth), the delivery device determiningportion 420 determines a delivery device that transmits the live videoimages to the viewing terminal 200. In specific terms, based on theprocessing shown in FIG. 11, the delivery device determining portion 420determines which is to be used from among the “delivery using thedelivery server”, the “delivery using one of the available deliveryterminals”, the “delivery using the n number of the available deliveryterminals” and the “direct delivery from the delivery terminal.”Further, when the delivery device determining portion 420 changes thedevice on the delivery side, the change is notified by the deliverydevice determining portion 420. In addition, the delivery devicedetermining portion 420 transmits an IP address of the device on thedelivery side to the viewing terminal 200, and also, the delivery devicedetermining portion 420 has a function of transmitting an IP address ofthe viewing terminal 200 to the device on the delivery side. Note thateach structural element shown in FIG. 12 can be formed by a circuit(hardware) or a central processing unit (CPU) and a program (software)that enables the circuit or the CPU to function. According to this typeof structure, the delivery management server 400 can dynamically changeand determine a type of the delivery device (the moving image deliveryserver 100 or the delivery terminal 300) and a number of the deliverydevices (the number of the delivery terminals 300) based on the numberof the viewers or the utilization bandwidth.

3. Processing Sequence of System According to Present Embodiment

FIG. 13 is a sequence diagram of a case in which use of the availabledelivery terminal 302 or of the moving image delivery server 100 newlystarts after the predicted number of viewers or the predictedutilization bandwidth increases during the delivery of the live videoimages. First, at step S60, the live video images are delivered from thedelivery terminal 300 to the viewing terminal 200. At step S62, theviewing terminal 200 is newly connected to the delivery managementserver 400. The delivery management server 400 determines the optimumdelivery method at a certain interval (step S64), and when it isdetermined that the available delivery terminal 302 or the moving imagedelivery server 100 should be newly used due to an increased number ofthe viewers, at step S66, a change of the delivery method is notified tothe delivery terminal 300. The delivery terminal 300 is connected to anewly specified terminal (step S68) while keeping a current deliverystatus, and starts delivering the moving images. In an example shown inFIG. 13, the delivery terminal 300 is connected to the availabledelivery terminal 302 at step S68. As a result, the available deliveryterminal 302 starts being used (step S70), and the live moving imagesare delivered from the delivery terminal 300 to the available deliveryterminal 302 (step S72). Further, at step S74, information noting thatthe available delivery terminal 302 will perform the delivery isnotified to a newly connected viewing terminal 200, and at step S76, thenewly connected viewing terminal 200 connects itself to the availabledelivery terminal 302. Then, at step S78, the moving images aredelivered from the available delivery terminal 302 to the newlyconnected viewing terminal 200. In this way, it is possible to newlydeliver the live video images from the available delivery terminal 302to the newly added viewing terminal 200.

FIG. 14 is a sequence diagram in a case in which use of the currentlyused available delivery terminal 302 or the moving image delivery server100 is finished after the predicted number of viewers or the predictedutilization bandwidth decreases. First, it is assumed that the movingimages are being delivered from the delivery terminal 300 to theavailable delivery terminal 302 or to the moving image delivery server100, and that the live video images are being delivered from theavailable delivery terminal 302 or from the moving image delivery server100 to the viewing terminal 200. Here, for the sake of simplifiedexplanation, it is assumed that the moving images are being deliveredfrom the delivery terminal 300 to the available delivery terminal 302(step S80) and the moving images are being delivered from the availabledelivery terminal 302 to the viewing terminal 200 (step S82). Thedelivery management server 400 determines the delivery method (stepS84), and when the delivery terminal is to be changed due to factorssuch as a decreased number of the viewers, information noting that thedelivery terminal 300 has been changed is notified to the viewingterminal 200 that is currently viewing the moving images (step S86).This notification includes information that specifies a delivery deviceafter the change. Based on the specification, the viewing terminal 200connects itself to the delivery terminal 300 (step S88) and receives themoving images from the delivery terminal 300 (step S90). In this way,since the viewing terminal 200 simultaneously receives two streams,namely the stream delivered at step S82 and the stream delivered at stepS90, when terminals to which the moving images are delivered areswitched, it can be inhibited for the moving images to be interrupted.When the viewing terminal 200 starts viewing the moving images from thedelivery terminal 300 at step S90, a connection between the viewingterminal 200 and the available delivery terminal 302 that is finishedbeing used is disconnected (step S92). After that, the deliverymanagement server 400 notifies the delivery terminal 300 of the changeof the delivery method (step S94), and the delivery terminal 300 cutsoff a connection with the available delivery terminal 302 that isfinished being used or with the moving image delivery server 100 (stepS96).

As described above, in the system according to the present invention,since live delivery is performed, unlike a Video on Demand (VoD)service, it is not possible to switch delivery methods while cachingvideo image data in advance. Therefore, in order to switch the deliverymethods seamlessly, two of the streams are simultaneously received asshown in FIG. 14. Note that, in the above-described example, an examplein which the delivery from the available delivery terminal 302 to theviewing terminal 200 is switched to the delivery from the deliveryterminal 300 to the viewing terminal 200 is described, but a similarprocess can be performed when the delivery from the available deliveryterminal 302 to the viewing terminal 200 is switched to the deliveryfrom the moving image delivery server 100 to the viewing terminal 200.

By simultaneously receiving the two streams as described with referenceto FIG. 14, it is possible to switch the delivery methods withoutinterrupting the moving images that are being viewed by the viewers,but, in this case, the bandwidth on the viewing terminal 200 side needsto be doubled temporarily. Here, for example, in a case of a bandwidthguaranteed type network, such as a Next Generation Network (NGN), sincea size of a guaranteed bandwidth used by a client may be limited or feesmay be charged per used bandwidth, it is assumed that it becomesnecessary to reduce the bandwidth used by the client when the deliverymethods are switched.

Given the above, FIG. 15 and FIG. 16 show a method to temporarilyestablish a connection to video image delivery using a narrow bandwidthwhen terminals are switched. As shown in FIG. 15, at first, at stepS100, the moving images are transmitted from a delivery terminal (A) 300to the viewing terminal 200. Next, at step S102, the moving images aredelivered from the delivery terminal (A) 300 to the viewing terminal 200using a wide bandwidth, and at the same time, the moving images aredelivered from a delivery terminal (B) 300 to the viewing terminal 200using the narrow bandwidth. Next, at step S104, the moving images aredelivered from the delivery terminal (A) 300 using the narrow bandwidth,and at the same time, the moving images are delivered from the deliveryterminal (B) 300 using the narrow bandwidth. Next, at step S106, themoving images are delivered from the delivery terminal (A) 300 using thenarrow bandwidth, and at the same time, the moving images are deliveredfrom the delivery terminal (B) 300 using the wide bandwidth. Accordingto the above-described method, even though the moving images aredelivered both from the delivery terminal (A) 300 and the deliveryterminal (B) 300, it is possible to inhibit an excessive increase of theutilization bandwidth. In this way, it is not necessary for thebandwidth on the viewing terminal 200 side to be doubled, and as long asthere is a sufficient bandwidth that can accommodate up to a total ofthe wide bandwidth and the narrow bandwidth at a maximum, it is possibleto switch the delivery methods seamlessly.

FIG. 16 is a sequence diagram showing the method illustrated in FIG. 15in detail. At first, at step S110, the moving images are delivered fromthe delivery terminal (B) 300 to the delivery terminal (A) 300 using thewide bandwidth. Next, at step S112, the moving images are delivered fromthe delivery terminal (A) 300 to the viewing terminal 200 using the widebandwidth. The delivery management server 400 monitors the number of theviewers, and when the delivery management server 400 detects a decreaseof the number of the viewers (step S114), it sends a notice to thedelivery terminal (A) 300 and to the delivery terminal (B) 300, thenotice stating that delivery of the moving images using the narrowbandwidth is to be started (step S116 and step S118).

Next, at step S120, a notice is sent from the delivery management server400 to the viewing terminal 200, the notice stating that the deliveryterminal has been changed. As a result, the viewing terminal 200establishes a connection with the delivery terminal (A) 300 using thenarrow bandwidth (step S122). At step S124, the delivery terminal (B)300 switches the bandwidth from the wide bandwidth to the narrowbandwidth with respect to the delivery of the moving images to thedelivery terminal (A) 300, the delivery terminal (B) 300 having receivedthe notice at step S118 stating that the delivery of the moving imagesusing the narrow bandwidth is to be started. Then, at step S126, thedelivery of the moving images using the narrow bandwidth is performedfrom the delivery terminal (A) 300 to the viewing terminal 200.

Next, at step S128, the connection between the viewing terminal 200 andthe delivery terminal (A) 300 using the wide bandwidth is disconnected.Then, at step S130, the viewing terminal 200 and the delivery terminal(B) 300 are connected using the narrow bandwidth, and at step S132, thedelivery of the moving images is performed from the delivery terminal(B) 300 to the viewing terminal 200 using the narrow bandwidth.

Next, at step S134, the connection between the viewing terminal 200 andthe delivery terminal (A) 300 using the narrow bandwidth isdisconnected. Next, at step S136, the viewing terminal 200 and thedelivery terminal (B) 300 are connected using the wide bandwidth, and atstep S138, the moving images are delivered from the delivery terminal(B) 300 to the viewing terminal 200 using the wide bandwidth. Then, atstep S140, the connection between the viewing terminal 200 and thedelivery terminal (B) 300 using the narrow bandwidth is disconnected.

According to the sequence shown in FIG. 16, since the viewing terminal200 is never connected to the delivery terminal (A) 300 and the deliveryterminal (B) 300 at the same time using the wide bandwidth of twostreams, it is possible to minimize an increase of the bandwidth.

As described above, according to the present embodiment, it becomespossible to select the optimum delivery method in advance fromperspectives including delivery cost of the live video images, and thenetwork bandwidth used for the delivery etc. Further, even while thevideo images are being delivered, it is possible to continue selectingthe optimum delivery method from perspectives including the deliverycost and the network bandwidth used for the delivery etc. In addition,it is possible to make a switch to the optimum delivery methodseamlessly, even while the video images are being delivered, and also,it is possible to make the switch to the optimum delivery method withoutinterrupting the video images that are being delivered while stoppinguse of the delivery terminal and the delivery server that are beingused. Further, when use of the delivery terminal and the delivery serverthat are being used is stopped, it is possible to stop using thedelivery terminal and the delivery server seamlessly while inhibiting anincrease of the network bandwidth on the viewing terminal side. Inaddition, according to the present embodiment, when a load on thedelivery server becomes high, it is possible to distribute the load byperforming the delivery from a delivery user and also, it becomespossible to predict the number of viewers for each delivery provider.Then, according to the present embodiment, it is possible to distributethe load by performing the delivery from the terminal without increasinga number of lines for the server.

The exemplary embodiments of the present invention are described indetail above with reference to the appended drawings. However, thepresent invention is not limited to the above-described examples. Itshould be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. An image delivery management server comprising: a delivery load amount acquiring portion that acquires a delivery load amount of an image that is delivered to a viewer's terminal connected via a network; and a delivery device determining portion that determines, based on the delivery load amount, a type or a quantity of a delivery device that performs image delivery to the viewer's terminal, wherein the delivery load amount acquiring portion includes a viewer's terminal information acquiring portion that acquires information relating to the viewer's terminal to which the image is delivered, wherein the delivery device determining portion determines the type or the quantity of the delivery device in accordance with the information relating to the viewer's terminal, wherein the information relating to the viewer's terminal includes at least a current or past number of viewers to which the image is delivered or a number of viewers who have reserved the image that is to be delivered, wherein the delivery load amount acquiring portion further includes a utilization bandwidth acquiring portion that acquires a utilization bandwidth of the network that is used by the image delivery, wherein the delivery device determining portion determines the type or the quantity of the delivery device based on a number of viewers and the utilization bandwidth, wherein the delivery device includes at least one of at least one delivery terminal that directly delivers the image to the viewer's terminal and a delivery server that delivers an image uploaded from the delivery terminal to the viewer's terminal, and wherein the delivery device determining portion determines the quantity of the delivery terminal that delivers the image to the viewer's terminal based on a predetermined threshold value relating to one of the number of viewers and the utilization bandwidth, and also determines whether only the delivery server delivers the image to the viewer's terminal.
 2. The image delivery management server according to claim 1, wherein the delivery device determining portion increases the quantity of the delivery terminal that delivers the image in accordance with an increase of one of the number of viewers and the utilization bandwidth, and determines that only the delivery server delivers the image to the viewer's terminal, when one of the number of viewers and the utilization bandwidth exceeds the predetermined threshold value.
 3. The image delivery management server according to claim 1, wherein the delivery device determining portion makes a switch from delivery using only the delivery server to delivery using a plurality of the delivery terminals, when one of the number of viewers and the utilization bandwidth becomes less than or equal to the predetermined threshold value, and also decreases the quantity of the delivery terminals by which the image is delivered in accordance with a further decrease of one of the number of viewers and the utilization bandwidth.
 4. The image delivery management server according to claim 3, wherein the delivery device determining portion causes both a device that is made to stop delivering and a device that is made to continue delivering to temporarily deliver an image stream, when the delivery using only the delivery server is switched to the delivery using the plurality of the delivery terminals or when the quantity of the delivery terminals is decreased.
 5. The image delivery management server according to claim 3, wherein the delivery device determining portion causes both the device that is made to stop delivering and the device that is made to continue delivering to temporarily deliver the image stream and also makes the bandwidth of each of the image stream narrower than usual, when the delivery using only the delivery server is switched to the delivery using the plurality of the delivery terminals or when the quantity of the delivery terminals is decreased. 